Of the hydrogenated block copolymers, a hydrogenated styrene-based thermoplastic elastomer is a thermoplastic elastomer excellent in weatherability, heat resistance, impact resistance, flexibility, and elastic recovery. A composition containing a hydrogenated block copolymer has been utilized in a wide variety of fields such as automobile supplies, home appliances, medical supplies, construction supplies, toys, daily necessities, and miscellaneous goods because the composition imparts an excellent mechanical strength, flexibility, weatherability, ozone resistance, heat stability, and transparency. In such circumstances, a hydrogenated product of a block copolymer obtained by copolymerizing a mixed monomer of isoprene and butadiene with styrene has been proposed for the purpose of improving the low-temperature characteristic, impact resistance, permanent set property, and mechanical strength of the hydrogenated styrene-based thermoplastic elastomer (see Patent Literature 1).
In addition, upon utilization of the excellent flexibility and elastic recovery of the hydrogenated styrene-based thermoplastic elastomer, a method involving mixing the elastomer with a plasticizer or various thermoplastic resins before its use has been proposed. For example, the following compositions have been proposed as such hydrogenated styrene-based thermoplastic elastomer composition: a composition formed of 20 to 80 wt % of an elastomer-like block copolymer, 5 to 60 wt % of a process oil, and 3 to 60 wt % of a vinylarene resin (see Patent Literature 2); a composition containing 52 to 60 wt % of a block polymer having at least two polystyrene terminal blocks and a mid block formed of a hydrogenated polymerized diene whose vinyl content is 45 wt % or less, 19 to 28 wt % of an oil, and 13 to 22 wt % of a polystyrene (see Patent Literature 3); and a composition formed of 35 to 50 parts by mass of a hydrogenated block copolymer having an aromatic vinyl content of 35 to 45 mass % and a weight-average molecular weight of 70,000 to 120,000, 30 to 50 parts by mass of a softener for a rubber, and 5 to 25 parts by mass of a polystyrene-based resin having a weight-average molecular weight of 100,000 to 400,000 (see Patent Literature 4).